All signs are pointing towards a refreshed MacBook Air being unveiled this week. Apple has yet to say anything official about the laptop but the rumor mill is pretty sure that it’s happening.

This rumor has been around for sometime now, but it’s looking more likely with every passing day. Right now we know that the current MacBook Air has outdated specifications, it hasn’t been refreshed in months, and it’s been outclassed by the competition. And we also know that Apple has an event called “Back to the Mac” planned for October 20th and that over the past weeks supplies of the Air have been depleting. Interesting…

The most interesting report so far comes from Apple Insider who says that on Wednesday Apple will relaunch a the MacBook Air with a model that was “redesigned from the ground up”. This subnotebook will have an 11.6-inch display, which is smaller than the 13.3-inch one found on the original MBA. The new model will also only use solid-state storage, though not necessarily by means of a standard SSD. Apple might have something clever in the works, like an “SSD stick” which changes the shape of the solid-state storage to something streamlined for the Air’s super-slim unibody design.

CNET independently reported that the new Air will be smaller than the previous one and that the price will be “significantly lower” than the current MBA’s $1499. They place the size at something between 13.3-inches and the iPad’s 9.7-inches, which points again towards 11.6-inches but they were not able to confirm that number. The outlet also said to expect to see the Nvidia MCP89 chipset and Intel Core 2 Duo processor, the same gear found on the 13.3-inch MacBook and MacBook Pro.

Finally, Engadget uncovered what looks to be a shot of the underside of a new Macbook Air. They say their model looks like another 13.3-incher, but that doesn’t mean it’s the only Air being released. This computer puts the external ports on both sides, not just one like the original Air, and it has more than one USB port. Also spotted were an SD card slot and Mini DisplayPort. They say this runs the same Intel Core 2 Duo SL9400 processor that the current Air users, which would be a serious disappointment, or it’s just a sign that this model is an early prototype.

A clever reader at Macrumor’s forums did some measuring and doesn’t agree with Engadget’s assessment though. Basing his measurements on the 12mm width of a USB slot he says the system is 230mm wide, which would make for a 10.1-inch display.

That’s a lot to take in, but don’t take it too seriously. We’ll know for sure in just two days.